Hydrotreating catalyst

ABSTRACT

An improved catalyst support and improved results in hydrotreating are obtained by preparing a catalyst comprising alumina surface treated with a very small amount of silica interacted with the alumina.

United States Patent I19} Braithwaite et al.

1 *Dec. 2, 1975 i 5 HYDROTREATING CATALYST [75] Inventors: David G. Braithwaite, Brookhaven,

Miss.; Carl F. Cross; Michael R. Basila, 3, both of Munster, Ind.

[73] Assignee: Nalco Chemical Company, Oak

Brook, Ill.

The portion of the term of this patent subsequent to Oct. 8, 1991, has been disciaimed.

[22] Filed: Mar. 22, i974 [21] Appl. No.: 453,941

Related Application Data [62] Division of Ser. No 277,733, Aug. 3, I972, Pat. No.

[ Notice:

[52] US. Cl 252/455 R {51 Int. Cl. B01J 29/06 [58] Field of Search 252/45 l 455 R [56] References Cited UNITED STATES PATENTS 3.840.477 l0/i974 Braithwaite ct al 252/455 R Primary ExaminerCarl F. Dees Attorney. Agent, or Firm-Johnston, Keil, Thompson & Shurtieff 9 Claims, No Drawings HYDROTREATING CATALYST This application is a division of application Ser. No. 277,733 filed Aug. 3, 1972, which has now matured between the silica and the alumina, as hereafter described.

DETAILED DESCRIPTION OF THE INVENTION into U.S. Pat. 3,840,477. 5 In practicing the invention it is desirable to effect interaction of the alumina with the silica by contacting BACKGROUND the alumina in the form of an extrudate, spheres or Alumina catalysts useful in a variety of fixed bed hybeads with a chemical reagent which tends to solubilize drotreating operations, e. g., hydrocracking, desulfurthe alumina at its surface so that the possibility of interization, hydrodenitrogenization and hydrogenation are action between the alumina and the silica is enhanced. well known. To accomplish this, the alumina beads or spheres or ex- Prior art alumina support materials have generally trudate either before, during or after the addition of silbeen prepared in the form of extrudates or pellets. Cerica as a silica sol or sodium silicate are brought into tain types of beaded or spherical alumina catalysts have contact with an activating agent which is effective to also been proposed. make the alumina more reactive with silica, either by The art of making catalysts is highly developed and converting a portion of the alumina to a water soluble over the years many improvements have been effected state or by adding a water soluble alumina compound. resulting in catalysts of a relatively high degree of so- It will be understood, therefore, that the term activatphistication and catalytic activity. In spite of the ading agent as used herein is intended to include and vanced state of the art, it would be highly desirable to cover various types of substances which will function industry to have available hydrotreating catalysts of infor the aforesaid purpose. Thus, it has been found that creased activities, so that a given amount of catalyst organic acids such as acetic acid and formic acid which will produce an ever-increasing amount of product and form water soluble aluminum salts can be employed for thus increase the productivity and improve the ecothis purpose. A strong organic base such as, for examnomics of the various hydrotreating operations. ple, tetramethylammonium hydroxide can also be used.

OB 1E CTS Another substance which can be employed as an activating agent is chlorohydrol which is a 50% by weight One of the objects of the present invention is to prosolution of hydrolyzed aluminum chloride containing vide a catalyst having an improved activity per unit aluminum hydroxide and aluminum chloride usually in amount of catalyst. a ratio of about one Cl per one or two Al. Another type Another object of the invention is to provide a new of activating agent which can be employed is aluminum and improved method of producing a catalyst of the isopropoxide dissolved in ethylene glycol monoethyltype described. ether (ethyl cellosolve) by boiling to eliminate the iso- Still a further object of the invention is to provide propyl alcohol. new and useful results in hydrotreating operations. A wide range of aqueous colloidal silica sols can be Other objects will appear hereinafter. used in practicing the invention. The ultimate particle size of the silica sol particles can range from 2 to 150 BRIEF SUMMARY OF THE INVENTION millimicrons and the surface area from 50 to 700 M /g. In accordance with the invention it has been found The sol can vary widely in SiO concentration, e.g., that an improved catalyst and catalyst support for use from 1 to by weight as SiO in hydrotreating can be obtained by coating alumina, Typical aqueous colloidal silica sols useful in prepare.g., extrudates, beads or spheres, usually having a diing the catalysts of the invention are set forth below in mension from about 0.01 inch to about 0.50 inch, with Table I:

TABLE I NALCOAG 1030 1034A 1035 1050 1060 1130 1140 Colloidal 30% 34% 35% 50% 50% 30% 40% Silica, as 510 pH 10.2 3.1 8.6 9.0 8.5 10.0 10.0 Ave.Particle 1 1-16 16-22 16-22 17-25 40-60 8 15 Size, millimicrons Ave.Surface Area, Mlgram 190-270 135-190 135-190 120-176 50-75 375 200 Specific 1.205 1.230 1.255 1.385 1.390 1.214 1.296 Gravity at 68F. Viscosity less less at 77Fcps than 5 than 5 S 70 5-l0 7 8 Na,0% 0.4% less 0.10% 0.30% 0.10% 0.65% 0.40%

than 0.01%

a small amount of silica, the amount of silica, as SiO in the resultant catalyst, after drying and calcining, being sufficient to enhance the activity of the alumina in hydrotreating but usually less than 2.5% by weight of the alumina, as A1 0 usually within the range of about 0.2% to 1.2% by weight. The catalyst is preferably prepared under conditions adapted to produce interaction In the silica sols given in Table I the liquid carrier for the SiO: particles is water but the sol can also be one in which at least a portion of the water is replaced by a water miscible alcohol or glycol. For example, NAL- COAG l 129 can be used which is an acid sol generally similar to NALCOAG 1034A except that a part of the water is replaced with isopropanol so that instead of water as a liquid carrier for the SiO the sol contains 40% to 50% isopropanol.

Since the amount of silica being added to the alumina in the form of a sol is extremely small, it is usually necessary to provide additional liquid carrier in the form of water or an aqueous solution of the activating agent in order to coat the alumina spheres.

While the activating agent can be added to the alumina shaped particles prior to the addition of the silica sol, it is usually more convenient to add the activating agent and silica sol simultaneously. Usually, therefore, the activating agent is mixed with the silica sol and the mixture is added to the alumina which is in the form of beads or spheres or an extrudate. The coated alumina particles are then dried and finally calcined. The drying step is preferably done at a temperature of at least 180C. for 1 hour. Longer drying times and higher or lower temperatures can be used. For example, the drying step might be conducted at temperatures of 30C. to 180C. with a longer drying time being required at the lower temperatures and a shorter drying time at the higher temperatures. The drying step removes enough moisture so that on subsequent calcining the evolution of water does not become too violent.

Calcining should be at temperatures in excess of 480C. (Ca 900F.) and preferably above 538C. (Ca 1000F.). A temperature of 594C. (Ca 1 100F.) achieves good results.

Where the activating agent is acidic, it is desirable to use an acidic silica sol. It is also desirable that the finished catalyst contain a low amount of sodium. Silica sols such as NALCOAG 1 129 and NALCOAG 1034A are preferred for the practice of the invention.

The amount of water or other water miscible carrier used with the silica particles should be sufficient so that the alumina particles are thoroughly wet. In any event,

however, the amount of silica is less than 2.5% by weight of the alumina.

The mixing of the alumina shaped particles with the silica sol and activating agent should be such as to insure intimate contact and coating of the alumina.

In order to evaluate the invention silica coated alumina spheres and alumina extrudates were subjected to a standard testing method in a hydrotreating process wherein the volume activity and weight activity of the catalyst of the invention were compared respectively with the volume activity and weight activity of a standard catalyst. The ratios of the respective activities then give a basis for determining the amount of enhanced activity. In the following examples it'will be understood that the volume activities and the weight activities are ratios of the activity of the catalyst tested to a standard catalyst having an activity of 1.0.

The invention will be further illustrated but is not limited by the following examples in which the quantities are stated in parts by weight unless otherwise indicated.

EXAMPLE I 500 grams of alumina spheres of approximately 41 inch diameter were mixed with 5 ml of NALCOAG 1034A and then with 500 grams of 50% acetic acid. The mixture was dried and then calcined at l 100F. for

2 hours.

EXAM PLE II 5 ml of NALCOAG 1034A was mixed with 500 grams of a 25% aqueous solution of tetramethylammo- 4 nium hydroxide and the resultant mixture was then mixed with 500grarns of Va inch diameter alumina spheres and allowed to air dry. The resultant product wasthen dried at 180C. for 1 hour and finally calcined at 1100F. for 2 hours.

EXAMPLE III 500 grams of a 14% aluminum isopropoxide solution in ethyl cellosolve was prepared by boiling the aluminum propoxide in the ethyl cellosolve with the elimination of isopropyl alcohol. 1.7 grams of NALCOAG l 129 was added to this solution and the resultant mixture was then mixed with 500 grams of Va inch diameter alumina spheres. Thereafter the coated alumina spheres were dried at 180C. for 2 hours and finally calcined at ll0OF. for 2 hours.

EXAMPLE IV The procedure was the same as in Example I except that 8 grams of 50% aqueous solution of gluconic acid was added to the mixture, the gluconic acid being added in this case as a stabilizing agent.

EXAMPLE V 14 grams of NALCOAG 1034A were mixed with 200 grams of a 50% aqueous solution of chlorohydrol and 300 grams of water. At this point a clear, slightly opalescent solution resulted. This was mixed with 500 grams of Va inch diameter alumina spheres. As these dried, the coated spheres became very sticky and formed clumps. After drying at 180C. for 1 hour and calcining at 1 F. for 2 hours, all tendencies to stick together disappeared.

EXAMPLE VI 20 grams of NALCOAG 1034A were mixed with 50 grams of formic acid and 450 grams of water. This mixture was then mixed with 500 grams of alumina spheres averaging one-eighth inch in diameter and allowed to air dry over night. The coated spheres were then dried at C. for 2 hours and calcined at 1100F. for 2 hours.

EXAMPLE VII 52 grams of silica acid sol (7% by weight SiO were mixed with 1500 grams of water. The diluted sol was then mixed with 600 grams of alumina spheres. The temperature of this mixture was raised to 180F. and held at 180 t 2F. for 1 hour. The liquid was drained from the spheres. The spheres were dried at 300F. for 2 hours and calcined at 1000F. for 2 hours.

EXAMPLE VIII 70 grams of sodium silicate solution (28.5% SiO, by weight) were mixed with 12.0 grams of sodium hydroxide pellets and 5000 grams of water. To this solution, 2040 grams of dry alumina powder were added. The temperature of this mixture was raised to 180F. and held at 180 i 2F. for one hour with constant stirring. The liquid was removed by filtration, and 5000 ml of water were passed through the resulting filter cake to remove any residual sodium hydroxide or sodium silicate. The material was oven dried, after which a small amount of water was added to adjust the moisture of the material to a level suitable for extrusion. The alumina was extruded into cylindrical particles about oneeighth inch long and one-sixteenth inch thick. The resulting formed alumina was-calcined in air at 1000F.

. for 2 hours.

EXAMPLEIX: l 1

246 grams of silica acid sol (7.0%"Si05 by weight) were mixed with 5000 grams" of water. The quantity of 2040 grams of dry alumina powder was added to this solution. The temperature of this mixture was raised to 180F. and held at 180 I 2 F. for -1hourwith constant stirring. The liquid was removedby filtration and 5000 ml of water were passed through theresulting filter cake to remove any residual unreacted silica. The material was oven dried. The materialwas extruded after adding a suitable amount of water. The extruded alumina was calcined in air at 1000F. for 2 hours.

EXAMPLE X 8 grams of sodium silicate were mixed with 1.5 grams of sodium hydroxide pellets and 500 grams of water. This solution was then mixed with 227 grams of 1/ 16 inch alumina pellets. The mixture was allowed to stand for 1 hour. The liquid was decanted and the pellets were then dried at 300F. for 2 hours and calcined at 1000F. for an additional 2 hours.

EXAMPLE XI for 2 hours and finally calcining at 1100F. for two hours. Evaluation data is given in Table I in which SA is surface area in square meters per gram and PV is pore value in cc per gram. The last column gives the comparative data for a standard catalyst where there was no silication of the alumina catalyst support.

The silica coated alumina particles prepared as described herein can be used as such in hydrotreating processes or they, can be used as catalyst supports for catalytically active metals, including one or more of the following:

For instance, as previously described, a hydrodesulfurization catalyst is made by depositing cobalt and molydenum upon the catalyst support.

The term hydrotreating refers to a reaction wherein mixtures of hydrocarbons are contacted with a catalyst in the presence of added hydrogen at elevated temperatures and pressures. In hydrocracking, which is one form of hydrotreating, higher boiling hydrocarbons are converted to lower boiling products. In desulfurization, the purpose of the hydrotreating process is to remove sulfur from the hydrocarbons. In hydrodenitrogenization the purpose of the hydrotreating process is to remove nitrogen compounds from the hydrocarbons. In hydrogenation the purpose of the hydrotreating process is to add hydrogen to the chemical structure of the hydrocarbons or to cause a rearrangement of the chemical structure by the addition of hydrogen.

The invention is hereby claimed as follows:

1. A process of preparing a catalyst or catalyst support which comprises mixing alumina particles in the form of spheres, pellets, or a powder with aqueous silica acid 501 in an amount and for a period of time sufficient to form a surface coating of SiO on said alumina which coating after removing excess liquid, drying and calcining constitutes less than 2.5% 810,, based on the weight of A1 0 but is sufficient to enhance the hydro- TABLE 1 Standard Catalyst EXAMPLE 1 11 111 IV. V Vl Vll Vlll IX X X1 No silication M 0; 12.2 13 .0 13.1 13.6 13.2 13.0 13.3 12.5 12.7 11.2 10.8 11.3 C00 3.6 3.5 3.5 3.6 2.8 3.5 3.5 3.3 3.0 2.6 2.9 2.8 1 .7 .75 .2 .8 .3, 2.0 .7 .9 .7 .8 1.0 0 M10: 83.0 83.0 83.0 82.0 84.0 81.0 82.0 82.0 83.0 85.0 84.0 85.0 %Si0, to A; .84 .90 .24 .98 .36 2.47 .85 1.1 .84 .94 1.2 0 SA 210 220 205 210 195 240 190 205 180 180 "PV 1200 A .69 56 .67 .67 .68 .68 .66 .53 .48 .47 .46 .47 WV 100 A .20 .21 .18 .21 .18. .26 .22 .25 .21 .22 .18 Apparent Bulk 1 Density 1 (glml) .53 .60 .54 .53 .53 .53 .54 .72 .72 .74 .75 .7 V01. Activity 1.3 1.3 1.3 1.3 1.2 1.1 1.2 1.6 1.3 1.2 1.1 1.0 Wt. Activity 1.2 1.1 1.2 1.2 1.1 1.0 1.1 1.6 1.3 1.3 1.2 1.0

'PV less than 1200 A "PV less than 100 A In the foregoing examples, the alumina consists essentially of pure alumina (A1 0 Compositions which are useful and procedures for preparing the beads or spheres include materials and processes described in one or more of U.S. Pat. Nos. 2,996,460 2,988,520, and 3,520,654. It should be understood that the invention is not limited to any particular method of preparing the beads or spheres or extrudates.

treating activity of said catalyst, and thereafter removing excess liquid, drying and calcining the resultant mixture.

2. A process as claimed in claim 1 in which said alumina particles have a diameter of from about 0.01 inch to about 0.50 inch.

3. A process as claimed in claim 1 in which said alumina particles are in spherical form.

4. A hydrotreating catalyst or catalyst support obtained according to the process claimed in claim 1.

5. A hydrotreating catalyst comprising a catalyst support as claimed in claim 4 and a catalytically active metal other than aluminum, said catalytically active metal being selected from the group consisting of Ni, Co, Fe, Mn, Cr, V, Cu, Zn, Mo, Pd, Sn, W, Mg, Re, lr, Os, Pt, Pb, Bi, and rare earths.

6. A hydrotreating catalyst as claimed in claim 5 wherein said catalytically active metal comprises cobalt and molybdenum.

7. A process as claimed in claim 1 in which the SiO is 0.2% to 1.2% by weight of the alumina.

8. A process as claimed in claim 1 in which said mixture is heated to a temperature of about F. after ter, extruded and calcined. 

1. A PROCESS OF PREPARING A CATALYST OR CATALYST SUPPORT WHICH COMPRISES MIXING ALUMINA PARTICLES IN THE FORM OF SPHERES, PELLETS, OR A POWDER WITH AQUEOUS SILICA ACID SOL IN AN AMOUNT AND FOR A PERIOD OF TIME SUFFICIENT TO FORM A SURFACE COATING OF SIO2 ON SAID ALUMINA WHICH COATING AFTER REMOVING EXCESS LIQUID, DRYING AND CALCINING CONSTITUTES LESS THAN 2.5% SIO2, BASED ON THE WEIGHT OF A12O3, BUT IS DUFFICIENT TO ENHANCE THE HYDROTREATING ACTIVITY OF SAID CATALYST, AND THEREAFTER REMOVING EXCESS LIQUID, DRYING AND CALCINING THE RESULTANT MIXTURE.
 2. A process as claimed in claim 1 in which said alumina particles have a diameter of from about 0.01 inch to about 0.50 inch.
 3. A process as claimed in claim 1 in which said alumina particles are in spherical form.
 4. A hydrotreating catalyst or catalyst support obtained according to the process claimed in claim
 1. 5. A hydrotreating catalyst comprising a catalyst support as claimed in claim 4 and a catalytically active metal other than aluminum, said catalytically active metal being selected from the group consisting of Ni, Co, Fe, Mn, Cr, V, Cu, Zn, Mo, Pd, Sn, W, Mg, Re, Ir, Os, Pt, Pb, Bi, and rare earths.
 6. A hydrotreating catalyst as claimed in claim 5 wherein said catalytically active metal comprises cobalt and molybdenum.
 7. A process as claimed in claim 1 in which the SiO2 is 0.2% to 1.2% by weight of the alumina.
 8. A process as claimed in claim 1 in which said mixture is heated to a temperature of about 180*F. after which excess liquid is removed and the resultant product is dried and calcined.
 9. A process as claimed in claim 1 in which said alumina particles are initially in the form of a powder which is mixed with said aqueous acid sol, the mixture heated to about 180*F., excess liquid is removed, the resultant product washed with water to remove any residual unreacted silica, thereafter dried, mixed with water, extruded and calcined. 